Interval clock



FIG. 1 is a front view showing the new design for an interval clock;

FIG. 2 is a left side view of the clock;

FIG. 3 is a right side view of the clock;

FIG. 4 is a view of the back of the clock;

FIG. 5 is a top view of the clock;

FIG. 6 is a bottom view of the clock; and,

FIG. 7 is a perspective view of the clock.

The broken lines in the drawings represent environment and form no part of the claimed design. 

CLAIM The ornamental design for an interval clock, as shown and described. 